ELECTROFACTS

INTRODUCTION Electronic blind stick is a simple tool that can help a blind person to detect obstacles like walls, tables, stairs, any sleepy liquid on the floor etc without touching them through an alarm system. This reduces the chances of any accident. Also if this blind stick falls down on ground,  then an automatic alarm starts ringing  so that its owner can easily find it even if he can’t see it. This blind stick is made at very low cost with a very simple circuit. WORKING Its working is very simple. It has two main parts: Sensors Signal Amplifier & Buzzer Fig:1 Fig:1 shows the block diagram of the complete system. Stick position detector, Liquid dirt detector and IR proximity sensor all of these come under 1st part i.e. sensors. Signal amplifier circuit and Buzzer comes under 2nd part. Different sensors detect different types of obstacles and generate an electrical signal. Those signals then go...

Resistors Bilateral, Passive, Linear Element Resistors oppose the flow of current flowing through it. Resistors obey Ohm's Law i.e. I ∝ v Resistors dissipates energy in the form of Heat S = σ + jω Complex Frequency σ = Attenuation Constant ω = Angular friquency Power Loss in resistor (P) P = V &times I = I 2 &times R = V 2 ÷ R Energy dissipated in Resistors as heat in Joules or Simply E R = I 2 &times R &times t = ( V 2 &times t ÷ R ) = ( V &times I &times t ) Change in Resistance due to change in dimension l = length of conductor A = Cross Sectional Area of the conductor ρ = Resistivity of condutor materil Change in Resistace due to change in temperature Let… R t = Resistance of material at temperature t. R 0 = Resistance of material at 0° temperature. α t = Tempera...

Electrical Circuit Elements can be  Linear or Non-Linear  Active or Passive  Unilateral or Bilateral  Time-Variant or Time-Invariant  Linear or Non-Linear  Linear Elements:  V-I characteristics follows only one equation of straight line passing through origine. Examples : Resistors, Inductors, Capacitors and Gyrator Non-Linear Elements:  Elements lacking any of the above mentioned characteristics for linear elements are Non-Linear Elements. Examples : Diodes, Transistors etc.. Active or Passive  Active Elements:  Active circuit elements have capacity of enhancing the energy level of signal passing through it. Slope of V-I characteristics of such elements is negative OR any part of V-I characteristics of such elements lies in 2nd or/and 4th Quadrant Example : Vacuum Tubes, Transistors, Power Sources... Passive Elements:  Passive elements can’t enhance the energy level of signals passing through...